Solid-state imaging device and electronic apparatus
The present technology relates to a solid-state imaging device and an electronic apparatus that enable simultaneous acquisition of a signal for generating a high dynamic range image and a signal for detecting a phase difference. The solid-state imaging device includes a plurality of pixel sets each including color filters of the same color, for a plurality of colors, each pixel set including a plurality of pixels. Each pixel includes a plurality of photodiodes PD. The present technology can be applied, for example, to a solid-state imaging device that generates a high dynamic range image and detects a phase difference, and the like.
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The present technology relates to a solid-state imaging device and an electronic apparatus, and more particularly, relates to a solid-state imaging device and an electronic apparatus configured to be able to simultaneously acquire a signal for generating a high dynamic range image and a signal for detecting a phase difference.
BACKGROUND ARTThere has been proposed a solid-state imaging device that achieves simultaneous acquisition of two types of pixel signals, a high-sensitivity signal and a low-sensitivity signal, for generating a high dynamic range image (hereinafter also referred to as an HDR image) and acquisition of a phase difference detection signal for distance measurement (see, for example, Patent Document 1).
CITATION LIST Patent Document
- Patent Document 1: Japanese Patent Application Laid-Open No. 2016-171308
In a pixel structure of Patent Document 1, three photodiodes are formed under one on-chip lens. If the curvature of the on-chip lens is increased to increase the refractive power to improve the angle dependence for specialization in phase difference characteristics, it becomes difficult to generate HDR images. Conversely, the curvature of the on-chip lens is reduced to reduce the refractive power to reduce the angle dependence for specialization in favorable generation of HDR images, the degree of separation of phase difference characteristics is deteriorated. Thus, it is difficult to achieve both phase difference characteristics and HDR characteristics. There has also been proposed a lens structure in which the curvature of one on-chip lens is changed, but it is sensitive to variation in shape, and thus is difficult to produce in large quantities.
The present technology has been made in view of such a situation, and is intended to enable simultaneous acquisition of a signal for generating a high dynamic range image and a signal for detecting a phase difference.
Solutions to ProblemsA solid-state imaging device according to a first aspect of the present technology includes a plurality of pixel sets each including color filters of the same color, for a plurality of colors, each pixel set including a plurality of pixels, each pixel including a plurality of photoelectric conversion parts.
An electronic apparatus according to a second aspect of the present technology includes a solid-state imaging device including a plurality of pixel sets each including color filters of the same color, for a plurality of colors, each pixel set including a plurality of pixels, each pixel including a plurality of photoelectric conversion parts.
In the first and second aspects of the present technology, a plurality of pixel sets each including color filters of the same color is provided for a plurality of colors, each pixel set is provided with a plurality of pixels, and each pixel is provided with a plurality of photoelectric conversion parts.
The solid-state imaging device and the electronic apparatus may be independent devices, or may be modules incorporated into other devices.
Effects of the InventionAccording to the first and second aspects of the present technology, it is possible to simultaneously acquire a signal for generating a high dynamic range image and a signal for detecting a phase difference.
Note that the effects described here are not necessarily limiting, and any effect described in the present disclosure may be included.
Hereinafter, a mode for carrying out the present technology (hereinafter referred to as an embodiment) will be described. Note that the description will be made in the following order.
1. Schematic configuration example of solid-state imaging device
2. First cross-sectional configuration example of pixels
3. Example of arrangement of color filters
4. Circuit configuration example of pixel set
5. Explanation of output modes
6. Modification of color array of color filters
7. Modification of orientations of photodiodes
8. Modification of on-chip lens arrangement
9. Second cross-sectional configuration example of pixels
10. Third cross-sectional configuration example of pixels
11. Configuration example in which light-shielding film is added
12. Other modifications
13. Pixel transistor arrangement example
14. Example of application to electronic apparatus
15. Example of application to endoscopic surgery system
16. Example of application to mobile object
<1. Schematic Configuration Example of Solid-State Imaging Device>
A solid-state imaging device 1 of
The pixels 2 each include photodiodes as photoelectric conversion parts and a plurality of pixel transistors. Note that, as described later with reference to
The control circuit 8 receives an input clock and data instructing an operation mode or the like, and outputs data such as internal information of the solid-state imaging device 1. Specifically, on the basis of a vertical synchronization signal, a horizontal synchronization signal, and a master clock, the control circuit 8 generates a clock signal and a control signal on the basis of which the vertical drive circuit 4, the column signal processing circuits 5, the horizontal drive circuit 6, and others operate. Then, the control circuit 8 outputs the generated clock signal and control signal to the vertical drive circuit 4, the column signal processing circuits 5, the horizontal drive circuit 6, and others.
The vertical drive circuit 4 is formed, for example, by a shift register, and selects a predetermined pixel drive wire 10, provides a pulse for driving the pixels 2 to the selected pixel thrive wire 10, and drives the pixels 2 row by row. That is, the vertical drive circuit 4 performs control to selectively scan the pixels 2 of the pixel array 3 in the vertical direction sequentially row by row, and output pixel signals based on signal charges generated in the photoelectric conversion parts of the pixels 2 depending on the amount of received light, through vertical signal lines 9 to the column signal processing circuits 5.
The column signal processing circuits 5 are arranged for the corresponding columns of the pixels 2, and perform signal processing such as noise removal on signals output from the pixels 2 in one row for the corresponding pixel columns. For example, the column signal processing circuits 5 perform signal processing such as correlated double sampling (CDS) for removing fixed pattern noise peculiar to pixels and AD conversion.
The horizontal drive circuit 6 is formed, for example, by a shift register, selects each of the column signal processing circuits 5 in order by sequentially outputting a horizontal scanning pulse, and causes each of the column signal processing circuits 5 to output a pixel signal to a horizontal signal line 11.
The output circuit 7 performs predetermined signal processing on a signal sequentially provided from each of the column signal processing circuits 5 through the horizontal signal line 11, and outputs the signal. For example, the output circuit 7 may perform only buffering, or may perform various types of digital signal processing such as black level adjustment and column variation correction. An input-output terminal 13 exchanges signals with the outside.
The solid-state imaging device 1 formed as described above is a CMOS image sensor called a column AD system in which the column signal processing circuits 5 that perform CDS processing and AD conversion processing are arranged for the corresponding pixel columns.
Furthermore, the solid-state imaging device 1 may be formed by a chip of a stacked structure in which a plurality of substrates is stacked. A chip with a plurality of substrates stacked is formed by stacking a lower substrate and an upper substrate in that order from below upward. At least one or more of the control circuit 8, the vertical drive circuit 4, the column signal processing circuits 5, the horizontal drive circuit 6, and the output circuit 7 are formed on the lower substrate, and at least the pixel array 3 is formed on the upper substrate. Connection portions connect the vertical drive circuit 4 to the pixel array 3, and the column signal processing circuits 5 to the pixel array 3, so that signals are transmitted between the lower substrate and the upper substrate. The connection portions are formed, for example, by through silicon vias (TSVs), Cu—Cu, or the like.
<2. First Cross-Sectional Configuration Example of Pixels>
In the pixel array 3 of the solid-state imaging device 1, photodiodes PD are formed by, for example, forming N-type (second conductivity type) semiconductor regions 32 in a P-type (first conductivity type) semiconductor region 31 in the semiconductor substrate 12. In each pixel 2 of the pixel array 3, two photodiodes PD are formed per pixel, and the two photodiodes PD are formed in such a manner as to be symmetrically disposed in two parts into which a pixel region is divided equally. Note that in the following description, of the two photodiodes PD formed in one pixel, the photodiode PD disposed on the right side in the figure is sometimes referred to as the right photodiode PD, and the photodiode PD disposed on the left side as the left photodiode PD.
On the front side of the semiconductor substrate 12 that is the lower side in
On the other hand, on pixel boundary portions on the back side of the semiconductor substrate 12 that is the upper side in
In addition, for example, an antireflection film (insulating layer) formed, for example, by a silicon oxide film or the like may be further formed on a back side interface of the semiconductor substrate 12.
On the back surface of the semiconductor substrate 12 including the inter-pixel light-shielding film 36, color filters 37 are formed. The color filters 37 are formed by spin-coating photosensitive resin containing coloring matters such as pigments or dyes, for example. The color array of the color filters 37 will be described later with reference to
On the color filters 37, on-chip lenses 38 are formed for the individual pixels. The on-chip lenses 38 are formed, for example, of a resin material such as a styrene resin, an acrylic resin, a styrene-acryl copolymer resin, or a siloxane resin.
As described above, the solid-state imaging device 1 is a back-side illuminated CMOS solid-state imaging device in which the color filters 37 and the on-chip lenses 38 are formed on the back side of the semiconductor substrate 12 opposite to the front side on which the multilayer wiring layer 35 is formed, so that light enters from the back side.
Each pixel 2 of the solid-state imaging device 1 has two separate photodiodes PD in the pixel. The two photodiodes PD are formed at different positions, so that a shift occurs between images generated from the two photodiodes PD, individually. From this image shift, the amount of phase shift is calculated to calculate the amount of defocus. By adjusting (moving) an imaging lens, autofocus can be achieved.
<3. Example of Arrangement of Color Filters>
Next, with reference to
In the pixel array 3 with the pixels 2 two-dimensionally arrayed in a matrix, four pixels 2 in 2×2 (two vertical pixels×two horizontal pixels) constitute one pixel set 51. And the color filters 37 are arranged to be of the same color in each individual pixel set 51. More specifically, the R, G, and B color filters 37 are arranged in a Bayer array in units of the pixel sets 51.
In
Furthermore, the orientations of the longitudinal shape of the two photodiodes PD formed in each pixel 2 are the same direction in the pixel set 51, and also, they are formed in the same direction in all the pixel sets 51.
The on-chip lenses 38 are formed for the individual pixels.
<4. Circuit Configuration Example of Pixel Set>
Next,
Each pixel 2 of the pixel set 51Gr includes two photodiodes PD and two transfer transistors TG for transferring charges accumulated in them. And one FD 52, one reset transistor 53, one amplification transistor 54, and one selection transistor 55 are provided for the pixel set 51Gr. Each of the reset transistor 53, the amplification transistor 54, and the selection transistor 55 is shared by the four pixels of the pixel set 51Gr. The four pixels sharing the reset transistor 53, the amplification transistor 54, and the selection transistor 5 form a sharing unit.
Rote that in the following, in a case where the two photodiodes PD and the two transfer transistors TG of each pixel 2 in the pixel set 51Gr are distinguished from each other, of the four pixels in 2×2 constituting the pixel set 51Gr, the two photodiodes PD of the upper left pixel 2 are referred to as photodiodes PD_Gr1L and PD_Gr1R, and the two transfer transistors TG that transfer charges accumulated in the photodiodes PD_Gr1L and PD_Gr1R are referred to as transfer transistors TG_Gr1L and TG_Gr1R.
Furthermore, the two photodiodes PD of the upper right pixel 2 are referred to as photodiodes PD_Gr2L and PD_Gr2R, and the two transfer transistors TG that transfer charges accumulated in the photodiodes PD_Gr2L and PD_Gr2R are referred to as transfer transistors TG_Gr2L and TG_Gr2R.
Likewise, the two photodiodes PD of the lower left pixel 2 are referred to as photodiodes PD_Gr3L, and PD_Gr3R, and the two transfer transistors TG that transfer charges accumulated in the photodiodes Gr3L and Gr3R are referred to as transfer transistors TG_Gr3L and TG_Gr3R. The two photodiodes PD of the lower right pixel 2 are referred to as photodiodes PD_Gr4L and PD_Gr4R, and the two transfer transistors TG that transfer charges accumulated in the photodiodes PD_Gr4L and PD_Gr4R are referred to as transfer transistors TG_Gr4L and TG_Gr4R.
Each of the photodiodes PD of each pixel 2 in the pixel set 51Gr receives light and generates and accumulates photocharges.
When a drive signal TRGGr1L provided to the gate electrode becomes active, the transfer transistor TG_Gr1L becomes conductive in response to this, transferring photocharges accumulated in the photodiode PD_Gr1L to the FD 52. When a drive signal TRGGr1R provided to the gate electrode becomes active, the transfer transistor TG_Gr1R becomes conductive in response to this, transferring photocharges accumulated in the photodiode PD_Gr1R to the FD 52.
When a drive signal TRGGr2L provided to the gate electrode becomes active, the transfer transistor TG_Gr2L becomes conductive in response to this, transferring photocharges accumulated in the photodiode PD_Gr2L to the FD 52. When a drive signal TRGGr2R provided to the gate electrode becomes active, the transfer transistor TG_Gr2R becomes conductive in response to this, transferring photocharges accumulated in the photodiode PD_Gr2R to the FD 52. The similar applies to the photodiodes PD_Gr3L, PD_Gr3R, PD_Gr4L, and PD_Gr4R, and the transfer transistors TG_Gr3L, TG_Gr3R, TG_Gr4L, and TG_Gr4R.
The PD 52 temporarily holds photocharges provided from each photodiode PD of each pixel 2 in the pixel set 51Gr.
When a drive signal RST provided to the gate electrode becomes active, the reset transistor 53 becomes conductive in response to this, resetting the potential of the FD 52 to a predetermined level (reset voltage VDD).
The amplification transistor 54 has a source electrode connected to the vertical signal line 9 via the selection transistor 55, thereby forming a source follower circuit with a load MOS of a constant current source circuit 56 connected to one end of the vertical signal line 9.
The selection transistor 55 is connected between the source electrode of the amplification transistor 54 and the vertical signal line 9. When a selection signal SEL provided to the gate electrode becomes active, the selection transistor 55 becomes conductive in response to this, bringing the sharing unit into a selected state and outputting pixel signals of the pixels 2 in the sharing unit output from the amplification transistor 54 to the vertical signal line 9. Note that for the pixel set 51 (the pixel set 51Gr in
The transfer transistors TG of the pixels 2, the reset transistor 53, the amplification transistor 54, and the selection transistor 55 are controlled by the vertical drive circuit 4.
In order to provide the drive signals TRGGr to the gate electrodes of the eight transfer transistors TG constituting the pixel set 51Gr, as illustrated in
The signal line 61-1 transmits the drive signal TRGGr1L to be provided to the gate electrode of the transfer transistor TG_Gr1L in the pixel set 51Gr. Furthermore, the signal line 61-1 also transmits the drive signal TRGGr1L to the gate electrode of a transfer transistor TG_R1L (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr1L in the pixel set 51Gr.
The signal line 61-2 transmits the drive signal TRGGr1R to be provided to the gate electrode of the transfer transistor TG_Gr1R in the pixel set 51Gr. Furthermore, the signal line 61-2 also transmits the drive signal TRGGr1R to the gate electrode of a transfer transistor TG_R1R (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr1R in the pixel set 51Gr.
The signal line 61-3 transmits the drive signal TRGGr2L to be provided to the gate electrode of the transfer transistor TG_Gr2L in the pixel set 51Gr. Furthermore, the signal line 61-3 also transmits the drive signal TRGGr2L to the gate electrode of a transfer transistor TG_R2L (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor G_Gr2L in the pixel set 51Gr.
The signal line 61-4 transmits the drive signal TRGGr2R to be provided to the gate electrode of the transfer transistor TG_Gr2R in the pixel set 51Gr. Furthermore, the signal line 61-4 also transmits the drive signal TRGGr2R to the gate electrode of a transfer transistor TG_R2R (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr2R in the pixel set 51Gr.
The signal line 61-5 transmits the drive signal TRGGr3L to be provided to the gate electrode of the transfer transistor TG_Gr3L in the pixel set 51Gr. Furthermore, the signal line 61-5 also transmits the drive signal TRGGr3L to the gate electrode of a transfer transistor TG_R3L (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr3L in the pixel set 51Gr.
The signal line 61-6 transmits the drive signal TRGGr3R to be provided to the gate electrode of the transfer transistor TG_Gr3R in the pixel set 51Gr. Furthermore, the signal line 61-6 also transmits the drive signal TRGGr3R to the gate electrode of a transfer transistor TG_R3R (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr3R in the pixel set 51Gr.
The signal line 61-7 transmits the drive signal TRGGr4L to be provided to the gate electrode of the transfer transistor TG_Gr4L in the pixel set 51Gr. Furthermore, the signal line 61-7 also transmits the drive signal TRGGr4L to the gate electrode of a transfer transistor TG_R4L (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr4L in the pixel set 51Gr.
The signal line 61-8 transmits the drive signal TRGGr4R to be provided to the gate electrode of the transfer transistor TG_Gr4R in the pixel set 51Gr. Furthermore, the signal line 61-8 also transmits the drive signal TRGGr4R to the gate electrode of a transfer transistor TG_R4R (not illustrated) in the pixel set 51R adjacent to the pixel set 51Gr, located at the same position as the transfer transistor TG_Gr4R in the pixel set 51Gr.
Likewise, eight signal lines 62-1 to 62-8 are required for the pixel sets 51B and 51Gb arrayed in the horizontal direction.
The signal line 62-1 transmits a drive signal TRGGb1L to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr1L in the pixel set 51Gr.
The signal line 62-2 transmits a drive signal TRGGb1R to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr1R in the pixel set 51Gr.
The signal line 62-3 transmits a drive signal TRGGb2L to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr2L in the pixel set 51Gr.
The signal line 62-4 transmits a drive signal TRGGb2R to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr2R in the pixel set 51Gr.
The signal line 62-5 transmits a drive signal TRGGb3L to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr3L in the pixel set 51Gr.
The signal line 62-6 transmits a drive signal TRGGb3R to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr3R in the pixel set 51Gr.
The signal line 62-7 transmits a drive signal TRGGb4L to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistors TG_Gr4L in the pixel set 51Gr.
The signal line 62-8 transmits a drive signal TRGGb4R to the gate electrodes of transfer transistors TG in the pixel sets 51B and 51Gb corresponding to the transfer transistor TG_Gr4R in the pixel set 51Gr.
By forming the circuit of the plurality of pixels 2 in the sharing unit as above, the pixels 2 in the sharing unit can output a pixel signal for each photodiode PD as a unit, and can output a pixel signal for each pixel as a unit or for a plurality of pixels as a unit, in response to a drive signal from the vertical drive circuit 4. In a case where a pixel signal is output for each pixel as a unit or for a plurality of pixels as a unit, a plurality of transfer transistors TG that outputs simultaneously is activated simultaneously. The FD 52 adds charges provided from a plurality of photodiodes PD via the transfer transistors TG simultaneously activated. Consequently, a pixel signal of each pixel as a unit or of a plurality of pixels as a unit is output from the ED 52 through the amplification transistor 54 and the selection transistor 55 to the column signal processing circuit 5.
Note that although
<5. Explanation of Output Mode>
<5.1 Full-Resolution Mode>
Next, a plurality of output modes that can be executed by the solid-state imaging device 1 will be described.
First, a full-resolution mode in which pixel signals generated in all the photodiodes PD in the pixel array 3 are output individually will be described.
A photodiode PD hatched in
In the example of
In the full-resolution mode, by combining pixel signals of the two photodiodes PD in the same pixel, a pixel signal of one pixel can be obtained, and by comparing the pixel signals of the two photodiodes PD in the same pixel, a phase difference can be detected. The other pixel sets 51Gb, 51R, and 51B perform an operation similar to that of the pixel set 51Gr in
Thus, in the full-resolution mode, all the pixels 2 can output a signal of each pixel as a unit and output signals for detecting a phase difference.
Furthermore, in the solid-state imaging device 1, the color filters 37 of R, G, or B are arranged in units of four pixels (in units of the pixel sets 51) as illustrated in
Note that in the full-resolution mode in which the drive in
For example, as illustrated in
Phase difference is detected using pixel signals of the photodiodes PD_Gr1L and PD_Gr1R of the upper left pixel 2 and the photodiodes PD_Gr4L and PD_Gr4R of the lower right pixel 2. Thus, by reducing the number of pixels 2 in which a phase difference is detected, the frame rate and the power consumption can be improved. Alternatively, pixels 2 in which a phase difference can be detected may be changed depending on difference in the amount of light received. For example, in low illumination, the drive in
The example of
<5.2 Four-Pixel Addition Phase-Difference Detection Mode>
Next, a four-pixel addition phase-difference detection mode will be described.
The solid-state imaging device 1 can execute the four-pixel addition phase-difference detection mode in which pixel signals are added and output in each pixel set 51 that is a sharing unit, that is, in units of four pixels in 2×2, and a phase difference is detected on the entire surface of the pixel array 3.
Also in
In the four-pixel addition phase-difference detection mode, the solid-state imaging device 1 adds and outputs pixel signals of photodiodes PD located at the same position in the pixels of the pixel set 51, of the pairs of photodiodes PD of the pixels 2. For example, as illustrated in A of
By performing such drive, a phase difference can be detected from a pixel signal of the left photodiodes PD and a pixel signal of the right photodiodes PD in each individual pixel set 51 read, and by combining the two pixel signals, a pixel signal output of each individual pixel set 51 (a unit of four pixels) can be obtained. In other words, an entire-surface phase difference can be detected while the advantage of a dynamic range due to increased pixel capacitance Qs is maintained.
As a method of discernably reading a pixel signal of left photodiodes PD and a pixel signal of right photodiodes PD, two ways can be adopted: a first reading method of separately reading a pixel signal of left photodiodes PD and a pixel signal of right photodiodes PD, and a second reading method of reading a signal obtained by adding a pixel signal of left photodiodes PD and a pixel signal of right photodiodes PD.
The first reading method and the second reading method will be briefly described.
First, the first reading method will be described.
First, while left and right photodiodes PD are receiving light (exposed), a dark level signal for performing correlated double sampling is acquired.
After the elapse of a predetermined exposure time, the solid-state imaging device 1 first reads a pixel signal of one of left and right photodiode PD groups of the pixel set 51, for example, a pixel signal of the left photodiode PD group.
For example, the reading of a pixel signal of the left photodiode PD group will be described with the example of the pixel set 51Gr illustrated in
The voltage signal output to the column signal processing circuit 5 is the sum of the pixel signal of the left photodiode PD group and the dark level signal. Thus, by subtracting the dark level signal from the voltage signal in the column signal processing circuit 5, the pixel signal of the left photodiode PD group is obtained.
Next, the solid-state imaging device 1 turns on the reset transistor 53 to reset the accumulated charges in the FD 52, and then reads a pixel signal of the other of the left and right photodiode PD groups of the pixel set 51, for example, a pixel signal of the right photodiode PD group. In the example of the pixel set 51Gr illustrated in
The voltage signal output to the column signal processing circuit 5 as the sum of the pixel signal of the right photodiode PD group and the dark level signal. Thus, by subtracting the dark level signal from the voltage signal in the column signal processing circuit 5, the pixel signal of the right photodiode PD group is obtained.
In the first reading method, a pixel signal of the left photodiodes PD and a pixel signal of the right photodiodes PD are read separately, so that a phase difference signal can be directly obtained. This allows acquisition of a high-quality signal for distance measurement. On the other hand, a signal for a captured image can be obtained by digitally adding signals of the left and right photodiodes PD.
Next, the second reading method will be described.
The second reading method is similar to the first reading method up until the acquisition of a dark level signal and the acquisition of a pixel signal of one of the left and right photodiode PD groups in the pixel set 51 (a pixel signal of the left photodiode PD group).
After acquiring a pixel signal of one of the left and right photodiode PD groups, the solid-state imaging device 1 does not turn on the reset transistor 53 (keeps it off) unlike the first reading method, and reads a pixel signal of the other of the left and right photodiode PD groups of the pixel set 51, for example, a pixel signal of the right photodiode PD group.
A voltage signal output to the column signal processing circuit 5 is the sum of the signals of the left and right photodiode PD groups and the dark level signal. The column signal processing circuit 5 first acquires the pixel signals of the left and right photodiode PD groups by subtracting the dark level signal from the voltage signal, and then acquires the pixel signal of the right photodiode PD group by subtracting the pixel signal of the left photodiode PD group obtained earlier from the pixel signals of the left and right photodiode PD groups.
In the second reading method, the pixel signal of the left photodiodes PD and the pixel signal of the right photodiodes PD can be acquired as above, and a phase difference signal can be obtained indirectly. On the other hand, signals for a captured image are added when they are analog, and thus have good signal quality, and also bring advantages in reading time and power consumption as compared with the first reading method.
<5.3 Four-Pixel Addition Mode>
Next, a four-pixel addition mode will be described.
In a case where phase difference information is not required, the solid-state imaging device 1 can execute the four-pixel addition mode in which pixel signals are added and output in each pixel set 51 that is a sharing unit, that is, in units of four pixels in 2×2.
In the four-pixel addition mode, all the (eight) transfer transistors TG in the pixel set 51 that is a sharing unit are simultaneously turned on, and charges in all the photodiodes PD in the pixel set 51 are provided to the FD 52. The FD 52 adds the charges of all the photodiodes PD in the pixel set 51. Then, a voltage signal corresponding to the added charges is output to the column signal processing circuit 5. By taking the difference between the voltage signal and a dark level signal, a pixel signal of each pixel set 51 can be acquired.
<5.4 First Phase Difference HDR Mode>
Next, a first phase difference HDR mode will be described.
The first phase difference HDR mode is an output mode that enables detection of a phase difference and generation of a high dynamic range image (hereinafter, referred to as an HDR image).
In order to detect phase difference, at least some of the plurality of pixels 2 constituting the pixel array 3 need to be pixels 2 that output a pixel signal of the left photodiode PD and a pixel signal of the right photodiode PD individually.
Furthermore, in order to generate an HDR image, the plurality of pixels 2 constituting the pixel array 3 needs to include pixels 2 different in exposure time.
Therefore, in the first phase difference HDR mode, the solid-state imaging device 1 sets two types of exposure times for the plurality of pixels 2 constituting the pixel array 3 as illustrated in
In the first phase difference HDR mode, one of a first exposure time and a second exposure time is set for each pixel. The second exposure time is an exposure time shorter than the first exposure time (first exposure time>second exposure time). In
As illustrated in
In the first phase difference HDR mode, as illustrated in
Specifically, the solid-state imaging device 1 simultaneously outputs pixel signals of a plurality of photodiodes PD in the order of pixel signals of all the photodiodes PD of the two upper right and lower left pixels 2, pixel signals of the left photodiodes PD of the upper left and lower right pixels 2, and pixel signals of the upper left and lower right photodiodes PD.
Consequently, the two pixels 2 whose exposure time is set to the second exposure time (S) output pixel signals of the left photodiode PD and the right photodiode PD separately, so that a phase difference can be detected. Furthermore, since the pixels 2 for which the first exposure time (L) is set and the pixels 2 for which the second exposure time (S) is set are included, an HDR image can be generated.
Note that the pixels 2 that detect a phase difference may be the pixels 2 whose exposure time is set to the first exposure time (L). However, if light intensity is high, the pixels 2 may be saturated. It is thus preferable that the pixels 2 that detect a phase difference are the pixels 2 for which the second exposure time (S) is set. By using the pixels 2 for which the second exposure time (S) is set as phase difference detection pixels, phase difference information can be acquired without causing saturation.
As described above, in the first phase difference HDR mode, for each pixel set 51, two types of exposure times, the first exposure time (L) and the second exposure time (S), are set, and in some of the pixels 2 of the pixel set 51, specifically, the pixels 2 for which the second exposure time (S) is set, pixel signals of the left and right photodiodes PD are separately output to detect a phase difference, so that signals for phase difference detection and signals of an HDR image with a high dynamic range can be simultaneously acquired.
<5.5 Second Phase Difference HDR Mode>.
Next, a second phase difference HDR mode will be described.
Like the first phase difference HDR mode, the second phase difference HDR mode is an output mode that enables phase difference detection and HDR image generation. The second phase difference HDR mode differs from the first phase difference HDR mode in that exposure times set for the pixels 2 in the pixel array 3 are not of the two types in the first phase difference HDR mode but of three types.
In the second phase difference HDR mode, one of first to third exposure times is set for each pixel. The second exposure time is an exposure time shorter than the first exposure time, and the third exposure time is an exposure time even shorter than the second exposure time (first exposure time>second exposure time>third exposure time). In
As illustrated in
In the second phase difference HDR mode, as illustrated in
Specifically, the solid-state imaging device 1 simultaneously outputs pixel signals of a plurality of photodiodes PD in the order of pixel signals of the two photodiodes PD of the upper right pixel 2, pixel signals of the left photodiodes PD of the upper left and lower right pixels 2, pixel signals of the right photodiodes PD of the upper left and lower right pixels 2, and pixel signals of the two photodiodes PD of the lower left pixel 2.
Consequently, the two pixels 2 whose exposure time is set to the second exposure time (M) output pixel signals of the left photodiode PD and the right photodiode PD separately, so that a phase difference can be detected. Furthermore, since the pixels 2 for which the different exposure times are set are included, an HDR image can be generated.
Note that the pixels 2 that detect a phase difference may be the pixels 2 whose exposure time is set to the first exposure time (L) or the third exposure time (S). However, if light intensity is high, the pixels 2 may be saturated, and if light intensity is low, the signal level may be too low. It is thus preferable to use the pixels 2 for which the second exposure time (M) for proper exposure is set. By using the pixels 2 for which the second exposure time (M) is set as phase difference detection pixels, phase difference information can be acquired without causing saturation.
As described above, in the second phase difference HDR mode, for each pixel set 51, three types of exposure times, the first exposure time (L), the second exposure time (M), and the third exposure tame (S), are set, and in some of the pixels 2 of each pixel set 51, specifically, the pixels 2 for which the second exposure time (N) is set, pixel signals of the left and right photodiodes PD are separately output to detect a phase difference, so that signals for phase difference detection and signals of an HDR image with a high dynamic range can be simultaneously acquired.
Note that in order to enable operation in both the first phase difference HDR mode and the second phase difference HDR mode, the eight signal lines 61-1 to 61-8 or 62-1 to 62-8 as illustrated in
For example,
In
Specifically, the single signal line 81-1 is disposed to control pixel signals of the left photodiodes PD of the pixels 2 paired in the diagonal direction for which an exposure time of the second exposure time (S) is set, and the single signal line 81-2 is disposed to control pixel signals of the right photodiodes PD. Furthermore, the single signal line 81-3 is disposed to control pixel signals of the left photodiodes PD of the pixels 2 paired in the diagonal direction for which an exposure time of the first exposure time (L) is set, and the single signal line 81-4 is disposed to control pixel signals of the right photodiodes PD side.
In
Specifically, the single signal line 82-1 is disposed to control pixel signals of the left photodiodes PD of the pixels 2 for which an exposure time of the first exposure time (L) is set, and the single signal line 82-2 is disposed to control pixel signals of the right photodiodes PD. Furthermore, the single signal line 82-3 is disposed to control pixel signals of the left photodiodes PD of the pixels 2 paired in the diagonal direction for which an exposure time of the second exposure time (M) is set, and the single signal line 82-4 is disposed to control pixel signals of the right photodiodes PD. The single signal line 82-5 is disposed to control pixel signals of the left photodiodes PD of the pixels 2 for which an exposure time of the third exposure time (S) is set, and the single signal line 82-6 is disposed to control pixel signals of the right photodiodes PD.
As described above, the solid-state imaging device 1 can execute, as an output mode, the full-resolution mode in which pixel signals of the photodiodes PD of each pixel 2 are output individually, the four-pixel addition phase-difference detection mode in which pixel signals of the left photodiodes PD or the right photodiodes PD are added and output in units of four pixels, the four-pixel addition mode in which pixel signals of all the photodiodes PD in the pixel set 51 are added and output, and the first phase difference HDR mode and the second phase difference HDR mode that enable phase difference detection and HDR image generation.
The full-resolution mode enables phase difference detection in all the pixels and high-resolution output by re-mosaicing, and the four-pixel addition phase-difference detection mode enables phase difference detection in the entire surface and high S/N and high dynamic range signal output by four-pixel addition. Furthermore, the four-pixel addition mode enables high S/N and high dynamic range signal output by four-pixel addition, and the first phase difference HDR mode and the second phase difference HDR mode enable both HDR image generation and phase difference detection in the entire surface. Note that to achieve HDR, two or more exposure times may be set for pixels with a single sensitivity as described above, or a single exposure time may be set for a plurality of pixels with different sensitivities formed as a pixel set. An example of a plurality of pixels with different sensitivities includes a pixel including photodiodes with a large light receiving area as a pixel with a high sensitivity, and a pixel including photodiodes with a small light receiving area as a pixel with a low sensitivity.
Note that, of course, the solid-state imaging device 1 may further be able to execute output modes other than those described above.
<6. Modification of Color Array of Color Filters>
In the above-described example, as illustrated in
In contrast, in
Thus, the color filters 37 may be arranged in a Bayer array in units of pixels.
The sharing unit of pixel circuits sharing the reset transistor 53, the amplification transistor 54, and the selection transistor 55 may be four pixels in 2×2 (two vertical pixels×two horizontal pixels) as in
<7. Modification of Orientations of Photodiodes>
In the above-described example, as illustrated in
However, the orientations of the longitudinal shape of the pairs of photodiodes PD is the pixels may be different from pixel to pixel or from pixel set to pixel set.
A of
In A of
B of
In B of
C of
In C of
As above, the two photodiodes PD of the longitudinal shape formed in each pixel are arranged symmetrically in the vertical direction or the horizontal direction, and for their orientations in the pixels in the pixel set 51, either the same direction or orthogonal directions can be used.
<8. Modification of On-Chip Lens Arrangement>
In the above-described example, as illustrated in
However, as illustrated in
A of
B of
C of
In the pixel array 3 in which the pixel sets 51 are two-dimensionally arranged, the on-chip lenses 91 in A to C of
The pixel set 51 with the on-chip lens 91 cannot acquire pixel signals for generating an HDR image, but can detect a phase difference with pixel signals in each pixel, and thus is effective for phase difference detection in low illumination.
<9. Second Cross-Sectional Configuration Example of Pixels>
In
The second cross-sectional configuration example of
Specifically, in the first cross-sectional configuration example illustrated in
As can be seen from the plan view of
<10. Third Cross-Sectional Configuration Example of Pixels>
In
In the second cross-sectional configuration example of
In the third cross-sectional configuration example of
As can be seen from the plan view of
The potential barrier between the two photodiodes PD in each pixel may be the same as the potential barrier at the pixel boundaries, or may be made lower than the potential barrier at the pixel boundaries as illustrated in B of
A of
As illustrated in B of
The height of the potential barrier between the photodiodes PD can be made lower than the potential barrier at the pixel boundaries by adjusting the impurity concentration in the impurity layer 102.
Note that the impurity layer 102 may be formed so as to completely isolate a region sandwiched between the two photodiodes PD as illustrated in
A cross-sectional view of parts where the impurity layer 102 is formed in
<11. Configuration Example in which Light-Shielding Film is Added>
In the above-described example, the inter-pixel light-shielding film 36 that prevent light from entering adjacent pixels are formed at pixel boundary portions, but no light-shielding film is formed on the photodiodes PD.
However, for some of the pixels 2 in the pixel array 3, a configuration in which a light-shielding film is disposed on two photodiodes PD in a pixel may be adopted.
In A and B of
A of
The on-chip lenses 38 are formed for the individual pixels as in
Using a pixel signal of the pixel set 51Gr in A of
In A and B of
A of
The on-chip lenses 38 are formed for the individual pixels as in
Using a pixel signal of the pixel set 51Gr in A of
Both of the first and second configurations in
In A and B of
A of
In
Using a pixel signal of the pixel set 51Gb in A of
In A and B of
A of
In
Using a pixel signal of the pixel set 51Gb in A of
Both of the third and fourth configurations in
In a case where the light intensity of incident light is high and phase difference information cannot be acquired in the pixel sets 51 at which no light-shielding film 121 is disposed, the first to fourth configurations of
The first to fourth configurations of
<12. Other Modifications>
In the example described above, the constituent units of the pixel set 51 is four pixels in 2×2 (two vertical pixels×two horizontal pixels). However, the pixel set 51 is not limited to four pixels in 2×2, and is only required to include a plurality of pixels 2.
In addition, for example, nine pixels in 3×3 (three vertical pixels×three horizontal pixels) may be set as constituent units of the pixel set 51.
In the example described above, a color filter 37 that allows light of wavelengths of R, G, or B to pass through is formed at each pixel 2 of the solid-state imaging device 1.
However, as illustrated in
Alternatively, instead of the color filters 37, the solid-state imaging device 1 may be provided with infrared filters that transmit infrared light to receive only infrared light to generate and output pixel signals.
<13. Pixel Transistor Arrangement Example>
An example of arrangement of pixel transistors will be described with reference to
In the pixel array 3, for example, the arrangement of the photodiodes PD and the pixel transistors illustrated in
In
As described with reference to
As illustrated in
With four photodiodes PD in 2×2 as a group, the transfer transistors TG provided one-to-one to the photodiodes PD are disposed near the center of the group. Four transfer transistors IG are collectively disposed near the center of four photodiodes PD in 2×2 in a right group in the pixel set 51, and four transfer transistors IG are collectively disposed near the center of four photodiodes PD in 2×2 in a left group in the pixel set 51.
The FD 52 includes at least metal wiring 52A as a part thereof. As illustrated in
Thus, for the shared pixel transistors (the reset transistor 53, the amplification transistor 54, and the selection transistor 55), a layout can be adopted in which they are disposed between the eight photodiodes PD of one pixel set 51 and the eight photodiodes PD of another pixel set 51 adjacent in the column direction. Note that although not illustrated, a layout in which the shared pixel transistors are disposed between the eight photodiodes PD and the eight photodiodes PD of the pixel sets 51 adjacent to each other in the row direction may be used.
<14. Example of Application to Electronic Apparatus>
The present technology is not limited to application to a solid-state imaging device. Specifically, the present technology is applicable to all electronic apparatuses using a solid-state imaging device for an image capturing unit (photoelectric conversion part), such as imaging apparatuses including digital still cameras and video cameras, portable terminal devices having an imaging function, and copying machines using a solid-state imaging device for an image reading unit. The solid-state imaging device may be formed as one chip, or may be in a modular form having an imaging function in which an imaging unit and a signal processing unit or an optical system are packaged together.
An imaging apparatus 200 in
The optical unit 201 captures incident light (image light) from a subject, forming an image on an imaging surface of the solid-state imaging device 202. The solid-state imaging device 202 converts the amount of incident light formed as the image on the imaging surface by the optical unit 201 into an electric signal pixel by pixel and outputs the electric signal as a pixel signal. As the solid-state imaging device 202, the solid-state imaging device 1 in
The display unit 205 includes, for example, a thin display such as a liquid crystal display (LCD) or an organic electroluminescence (EL) display, and displays a moving image or a still image captured by the solid-state imaging device 202. The recording unit 206 records a moving image or a still image captured by the solid-state imaging device 202 on a recording medium such as a hard disk or a semiconductor memory.
The operation unit 207 issues operation commands on various functions of the imaging apparatus 200 under user operation. The power supply 208 appropriately supplies various power supplies to be operation power supplies for the DSP circuit 203, the frame memory 204, the display unit 205, the recording unit 206, and the operation unit 207, to them to be supplied with.
As described above, by using the solid-state imaging device 1 to which the above-described embodiment is applied as the solid-state imaging device 202, it is possible to simultaneously acquire a signal for generating a high dynamic range image and a signal for detecting a phase difference. Therefore, the imaging apparatus 200 such as a video camera or a digital still camera, or further a camera module for a mobile device such as a portable phone can also improve the quality of captured images.
<Example of Use of Image Sensor>
The image sensor using the above-described solid-state imaging device 1 can be used in various cases where light such as visible light, infrared light, ultraviolet light, and X-ray are sensed, for example, as below.
-
- Devices for capturing images for viewing, such as digital cameras and portable devices with a camera function
- Devices for transportation use, such as vehicle-mounted sensors for imaging the front, back, surroundings, interior, etc. of a vehicle, surveillance cameras for monitoring running vehicles and roads, and distance measurement sensors for measuring distance between vehicles or the like, for safe driving such as automatic stopping, recognition of drivers' conditions, and the like
- Devices used in household appliances such as TVs, refrigerators, and air conditioners, for imaging user gestures and performing apparatus operations in accordance with the gestures
- Devices for medical treatment and healthcare use, such as endoscopes and devices that perform blood vessel imaging through reception of infrared light
- Devices for security use, such as surveillance cameras for crime prevention applications and cameras for person authentication applications
- Devices for beautification use, such as skin measuring instruments for imaging skin and microscopes for imaging scalp
- Devices for sports use, such as action cameras and wearable cameras for sports applications and the like
- Devices for agriculture use, such as cameras for monitoring the conditions of fields and crops
<15. Example of Application to Endoscopic Surgery System>
The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.
The endoscope 11100 includes a lens tube 11101 with a region of a predetermined length from the distal end inserted into the body cavity of the patient 11132, and a camera head 11102 connected to the proximal end of the lens tube 11101. In the illustrated example, the endoscope 11100 formed as a so-called rigid scope having a rigid lens tube 11101 is illustrated, but the endoscope 11100 may be formed as a so-called flexible scope having a flexible lens tube.
An opening in which an objective lens is fitted is provided at the distal end of the lens tube 11101. A light source device 11203 is connected to the endoscope 11100. Light generated by the light source device 11203 is guided to the distal end of the lens tube 11101 through a light guide extended inside the lens tube 11101, and is emitted through the objective lens toward an object to be observed in the body cavity of the patient 11132. Note that the endoscope 11100 may be a forward-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.
An optical system and an imaging device are provided inside the camera head 11102. Light reflected from the object being observed (observation light) is concentrated onto the imaging device by the optical system. The observation light is photoelectrically converted by the imaging device, and an electric signal corresponding to the observation light, that is, an image signal corresponding to an observation image is generated. The image signal is transmitted to a camera control unit (CCU) 11201 as RAW data.
The CCU 11201 includes a central processing unit (CPU), a graphics processing unit (CPU), or the like, and performs centralized control on the operations of the endoscope 11100 and a display device 11202. Moreover, the CCU 11201 receives an image signal from the camera head 11102, and performs various types of image processing such as development processing (demosaicing) on the image signal for displaying an image based on the image signal.
The display device 11202 displays an image based on an image signal subjected to image processing by the CCU 11201 under the control of the CCU 11201.
The light source device 11203 includes a light source such as a light emitting diode (LED), and supplies irradiation light when a surgical site or the like is imaged to the endoscope 11100.
An input device 11204 is an input interface for the endoscopic surgery system 11000. The user can input various types of information and input instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to chance conditions of imaging by the endoscope 11100 (the type of irradiation light, magnification, focal length, etc.) and the like.
A treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for tissue ablation, incision, blood vessel sealing, or the like. A pneumoperitoneum device 11206 feeds gas into the body cavity of the patient 11132 through the pneumoperitoneum tube 11111 to inflate the body cavity for the purpose of providing a field of view by the endoscope 11100 and providing the operator's workspace. A recorder 11207 is a device that can record various types of information associated with surgery. A printer 11208 is a device that can print various types of information associated with surgery in various forms including text, an image, and a graph.
Note that the light source device 11203 that supplies irradiation light when a surgical site is imaged to the endoscope 11100 may include a white light source including LEDs, laser light sources, or a combination of them, for example. In a case where a white light source includes a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high accuracy. Thus, the light source device 11203 can adjust the white balance of captured images. Furthermore, in this case, by irradiating an object to be observed with laser light from each of the RGB laser light sources in a time-division manner, and controlling the drive of the imaging device of the camera head 11102 in synchronization with the irradiation timing, images corresponding one-to-one to RGB can also be imaged in a time-division manner. According to this method, color images can be obtained without providing color filters at the imaging device.
Furthermore, the drive of the light source device 11203 may be controlled so as to change the intensity of output light every predetermined time. By controlling the drive of the imaging device of the camera head 11102 in synchronization with the timing of change of the intensity of light and acquiring images in a time-division manner, and combining the images, a high dynamic range image without so-called underexposure and overexposure can be generated.
Furthermore, the light source device 11203 may be configured to be able to supply light in a predetermined wavelength band suitable for special light observation. In special light observation, for example, so-called narrow band imaging is performed in which predetermined tissue such as a blood vessel an a superficial portion of a mucous membrane is imaged with high contrast by irradiating it with light in a narrower band than irradiation light at the time of normal observation (that is, white light), utilizing the wavelength dependence of light absorption in body tissue. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained by fluorescence generated by irradiation with excitation light. Fluorescence observation allows observation of fluorescence from body tissue by irradiating the body tissue with excitation light (autofluorescence observation), acquisition of a fluorescence image by locally injecting a reagent such as indocyanine green (ICG) into body tissue and irradiating the body tissue with excitation light corresponding to the fluorescence wavelength of the reagent, and the like. The light source device 11203 can be configured to be able to supply narrowband light and/or excitation light suitable for such special light observation.
The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are communicably connected to each other by a transmission cable 11400.
The lens unit 11401 is an optical system provided at a portion connected to the lens tube 11101. Observation light taken in from the distal end of the lens tube 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 includes a combination of a plurality of lenses including a zoom lens and a focus lens.
The imaging unit 11402 includes an imaging device. The imaging unit 11402 may include a single imaging device be of a so-called single plate type), or may include a plurality of imaging devices (be of a so-called multi-plate type). In a case where the imaging unit 11402 is of the multi-plate type, for example, image signals corresponding one-to-one to RGB may be generated by imaging devices, and they may be combined to obtain a color image. Alternatively, the imaging unit 11402 may include a pair of imaging devices for acquiring right-eye and left-eye image signals corresponding to a 3D (dimensional) display, individually. By performing 3D display, the operator 11131 can more accurately grasp the depth of living tissue at a surgical site. Note that in a case where the imaging unit 11402 is of the multi-plate type, a plurality of lens units 11401 may be provided for the corresponding imaging devices.
Furthermore, the imaging unit 11402 may not necessarily be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens tube 11101 directly behind the objective lens.
The drive unit 11403 includes an actuator, and moves the zoom lens and the focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. With this, the magnification and focus of an image captured by the imaging unit 11402 can be adjusted as appropriate.
The communication unit 11404 includes a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits an image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.
Furthermore, the communication unit 11404 receives a control signal for controlling the drive of the camera head 11102 from the CCU 11201, and provides the control signal to the camera head control unit 11405. The control signal includes, for example, information regarding imaging conditions such as information specifying the frame rate of captured images, information specifying the exposure value at the time of imaging, and/or information specifying the magnification and focus of captured images.
Note that the imaging conditions such as the frame rate, the exposure value, the magnification, and the focus described above may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 on the basis of an acquired image signal. In the latter case, so-called an auto exposure (AE) function, an auto focus (AF) function, and an auto white balance (AWB) function are mounted on the endoscope 11100.
The camera head control unit 11405 controls the drive of the camera head 11102 on the basis of a control signal from the CCU 11201 received via the communication unit 11404.
The communication unit 11411 includes a communication device for transmitting and receiving various types of information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.
Furthermore, the communication unit 11411 transmits a control signal for controlling the drive of the camera head 11102 to the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.
The image processing unit 11412 performs various types of image processing on an image signal that is RAW data transmitted from the camera head 11102.
The control unit 11413 performs various types of control for imaging of a surgical site or the like by the endoscope 11100 and display of a captured image obtained by imaging of a surgical site or the like. For example, the control unit 11413 generates a control signal for controlling the drive of the camera head 11102.
Furthermore, the control unit 11413 causes the display device 11202 to display a captured image showing a surgical site or the like, on the basis of an image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, by detecting the shape of the edge, the color, or the like of an object included in a captured image, the control unit 11413 can recognize a surgical instrument such as forceps, a specific living body part, bleeding, mist when the energy treatment instrument 11112 is used, and so on. When causing the display device 11202 to display a captured image, the control unit 11413 may superimpose various types of surgery support information on an image of the surgical site for display, using the recognition results. By the surgery support information being superimposed and displayed, and presented to the operator 11131, the load of the operator 11131 can be reduced, and the operator 11131 can reliably proceed with the surgery.
The transmission cable 11400 that connects the camera head 11102 and the CCU 11201 is an electric signal cable for electric signal communication, an optical fiber for optical communication, or a composite cable for them.
Here, in the illustrated example, communication is performed by wire using the transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed by radio.
An example of the endoscopic surgery system to which the technology according to the present disclosure can be applied has so far been described. The technology according to the present disclosure can be applied to the imaging unit 11402 in the configuration described above. Specifically, the solid-state imaging device 1 according to the above-described embodiment can be applied as the imaging unit 11402. By applying the technology according to the present disclosure to the imaging unit 11402, it is possible to simultaneously acquire a signal for generating a high dynamic range image and a signal for detecting a phase difference. Consequently, a high-quality captured image and distance information can be acquired, and the degree of safety of the driver and the vehicle can be increased.
Note that although the endoscopic surgery system has been described here as an example, the technology according to the present disclosure may be applied, for example, to a microsurgery system and the like.
<16. Example of Application to Mobile Object>
The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be implemented as a device mounted on any type of mobile object such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, and a robot.
A vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example illustrated in
The drive system control unit 12010 controls the operation of apparatuses related to the drive system of the vehicle, according to various programs. For example, the drive system control unit 12010 functions as a control device for a driving force generation apparatus for generating a driving force of the vehicle such as an internal combustion engine or a drive motor, a driving force transmission mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a vehicle braking force, and others.
The body system control unit 12020 controls the operation of various apparatuses mounted on the vehicle body, according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, power window devices, or various lamps including headlamps, back lamps, brake lamps, indicators, and fog lamps. In this case, the body system control unit 12020 can receive the input of radio waves transmitted from a portable device that substitutes for a key or signals from various switches. The body system control unit 12020 receives the input of these radio waves or signals, and controls door lock devices, the power window devices, the lamps, and others of the vehicle.
The vehicle exterior information detection unit 12030 detects information regarding the exterior of the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the vehicle exterior information detection unit 12030. The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image outside the vehicle and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing on a person, a vehicle, an obstacle, a sign, characters on a road surface, or the like, on the basis of the received image.
The imaging unit 12031 is an optical sensor that receives light and outputs an electric signal corresponding to the amount of the received light. The imaging unit 12031 may output an electric signal as an image, or may output it as distance measurement information. Furthermore, light received by the imaging unit 12031 may be visible light, or may be invisible light such as infrared rays.
The vehicle interior information detection unit 12040 detects information of the vehicle interior. For example, a driver condition detection unit 12041 that detects a driver's conditions is connected to the vehicle interior information detection unit 12040. The driver condition detection unit 12041 includes, for example, a camera that images the driver. The vehicle interior information detection unit 12040 may calculate the degree of fatigue or the degree of concentration of the driver, or may determine whether the driver is dozing, on the basis of detected information input from the driver condition detection unit 12041.
The microcomputer 12051 can calculate a control target value for the driving force generation apparatus, the steering mechanism, or the braking device on the basis of vehicle interior or exterior information acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control for the purpose of implementing the functions of an advanced driver assistance system (ADAS) including vehicle collision avoidance or impact mitigation, following driving based on inter-vehicle distance, vehicle speed-maintaining driving, vehicle collision warning, vehicle lane departure warning, and so on.
Furthermore, the microcomputer 12051 can perform cooperative control for the purpose of automatic driving for autonomous travelling without a driver's operation, by controlling the driving force generation apparatus, the steering mechanism, the braking device, or others, on the basis of information around the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040.
Moreover, the microcomputer 12051 can output a control command to the body system control unit 12020 on the basis of vehicle exterior information acquired by the vehicle exterior information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control for the purpose of preventing glare by controlling the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the vehicle exterior information detection unit 12030, switching high beam to low beam, or the like.
The sound/image output unit 12052 transmits an output signal of at least one of a sound or an image to an output device that can visually or auditorily notify a vehicle occupant or the outside of the vehicle of information. In the example of
In
The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, the side mirrors, the rear bumper or the back door, and an upper portion of the windshield in the vehicle compartment of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper portion of the windshield in the vehicle compartment mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or the back door mainly acquires images of the rear of the vehicle 12100. Front images acquired by the imaging units 12101 and 12105 are mainly used for detection of a preceding vehicle, or a pedestrian, an obstacle, a traffic light, or a traffic sign, or a lane, or the like.
Note that
At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera including a plurality of imaging devices, or may be an imaging device including pixels for phase difference detection.
For example, the microcomputer 12051 can determine distances to three-dimensional objects in the imaging ranges 12111 to 12114, and temporal changes in the distances (relative speeds to the vehicle 12100), on the basis of distance information obtained from the imaging units 12101 to 12104, thereby extracting, as a preceding vehicle, especially the nearest three-dimensional object located on the traveling path of the vehicle 12100 which is a three-dimensional object traveling at a predetermined speed (e.g., 0 km/h or higher) in substantially the same direction as the vehicle 12100. Furthermore, the microcomputer 12051 can perform automatic brake control (including following stop control), automatic acceleration control (including following start control), and the like, setting an inter-vehicle distance to be provided in advance in front of a preceding vehicle. Thus, cooperative control for the purpose of autonomous driving for autonomous traveling without a driver's operation or the like can be performed.
For example, the microcomputer 12051 can extract three-dimensional object data regarding three-dimensional objects, classifying them into a two-wheel vehicle, an ordinary vehicle, a large vehicle, a pedestrian, and another three-dimensional object such as a power pole, on the basis of distance information obtained from the imaging units 12101 to 12104, for use in automatic avoidance of obstacles. For example, for obstacles around the vehicle 12100, the microcomputer 12051 distinguishes between obstacles that can be visually identified by the driver of the vehicle 12100 and obstacles that are difficult to visually identify. Then, the microcomputer 12051 determines a collision risk indicating the degree of danger of collision with each obstacle. In a situation where the collision risk is equal to or higher than a set value and there is a possibility of collision, the microcomputer 12051 can perform driving assistance for collision avoidance by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or performing forced deceleration or avoidance steering via the drive system control unit 12010.
At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in captured images of the imaging units 12101 to 12104. The recognition of a pedestrian is performed, for example, by a procedure of extracting feature points in captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching on a series of feature points indicating the outline of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the sound/image output unit 12052 controls the display unit 12062 to superimpose and display a rectangular outline for enhancement on the recognized pedestrian. Alternatively, the sound/image output unit 12052 may control the display unit 12062 so as to display an icon or the like indicating the pedestrian at a desired position.
An example of the vehicle control system to which the technology according to the present disclosure can be applied has so far been described. The technology according to the present disclosure can be applied to the imaging unit 12031 in the configuration described above. Specifically, the solid-state imaging device 1 according to the above-described embodiment can be applied as the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, a signal for generating a high dynamic range image and a signal for detecting a phase difference can be acquired simultaneously. Consequently, a high-quality captured image and distance information can be acquired, and the degree of safety of the driver and the vehicle can be increased.
In the above-described examples, the solid-state imaging device that uses electrons as signal charges with the first conductivity type as P-type and the second conductivity type as N-type has been described. The present technology is also applicable to a solid-state imaging device that uses holes as signal charges. That is, with the first conductivity type as N-type and the second conductivity type as P-type, each semiconductor region described above can be formed by a semiconductor region of the opposite conductivity type.
Embodiments of the present technology are not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present technology.
For example, a form combining all of or part of the embodiments described above can be used.
It should be noted that the effects described in the present description are merely examples and not limiting. Effects other than those described in the present description may be included.
Note that the present technology can also take the following configurations.
(1)
A solid-state imaging device including:
a plurality of pixel sets each including color filters of the same color, for a plurality of colors, each pixel set including a plurality of pixels, each pixel including a plurality of photoelectric conversion parts.
(2)
The solid-state imaging device according to (1) described above, in which
each pixel includes two photoelectric conversion parts disposed symmetrically in a vertical direction os a horizontal direction, and
orientations of the photoelectric conversion parts of the pixels are the same direction at least in each individual pixel set.
(3)
The solid-state imaging device according to (2) described above, in which
the orientations of the photoelectric conversion parts of the pixels are the same direction in all the pixel sets.
(4)
The solid-state imaging device according to (1) described above, in which
each pixel includes two photoelectric conversion parts disposed symmetrically in a vertical direction or a horizontal direction, and
orientations of the photoelectric conversion parts of two of the pixels arranged in the horizontal direction in each pixel set are the same direction.
(5)
The solid-state imaging device according to described above, in which
each pixel includes two photoelectric conversion parts disposed symmetrically is a vertical direction or a horizontal direction, and
orientations of the photoelectric conversion parts of two of the pixels arranged in the horizontal direction in each pixel set are orthogonal directions.
(6)
The solid-state imaging device according to any one of (1) to (5) described above, in which
the plurality of photoelectric conversion parts of each pixel is isolated from each other by an insulating layer.
(7)
The solid-state imaging device according to any one of (1) to (5) described above, is which
the plurality of photoelectric conversion parts of each pixel is isolated from each other by an impurity layer of a conductivity type opposite to a conductivity type of the photoelectric conversion parts.
(8)
The solid-state imaging device according to (7) described above, in which
the impurity layer forms a potential barrier lower than a potential barrier at pixel boundaries.
(9)
The solid-state imaging device according to any one of (1) to (8) described above, in which
a light-shielding film is formed at some of the plurality of pixel sets, the light-shielding film partly shielding ail the pixels in each pixel set from light.
(10)
The solid-state imaging device according to any one of (1) to (8) described above, is which
a light-shielding film is formed at some of toe plurality of pixel sets, the light-shielding film entirely shielding some of the pixels in each pixel set from light.
(11)
The solid-state imaging device according to any one of (1) to (10) described above, further including:
a charge holding part that holds charges generated in the photoelectric conversion parts,
the charge holding part adding and outputting charges generated in the photoelectric conversion parts of the plurality of pixels.
(12)
The solid-state imaging device according to (11) described above, in which
the charge holding part adds and outputs charges generated in the photoelectric conversion parts of all the pixels in each pixel set.
(13)
The solid-state imaging device according to (11) described above, in which
the charge holding part adds and outputs charges in the photoelectric conversion parts whose positions in the pixels are the same position, of the photoelectric conversion parts of the plurality of pixels included in each pixel set.
(14)
The solid-state imaging device according to any one of (1) to (13) described above, in which
of the photoelectric conversion parts of the plurality of pixels included in each pixel set, a first photoelectric conversion part and a second photoelectric conversion part are exposed for different exposure times.
(15)
The solid-state imaging device according to (14) described above, further including:
a control unit that performs control to output charges of light received by each photoelectric conversion part as a pixel signal,
the control unit outputting a first pixel signal of the first photoelectric conversion part exposed for a first exposure time, and outputting a second pixel signal of the second photoelectric conversion part exposed for a second exposure time.
(16)
The solid-state imaging device according to any one of (1) to (15) described above, in which
pixel signals generated in the plurality of photoelectric conversion parts of at least some of the plurality of pixels included in each pixel set are output separately.
(17)
The solid-state imaging device according to any one of (1) to (16) described above, in which
of the plurality of pixels included in each pixel set, the photoelectric conversion parts of a first pixel are exposed for a first exposure time, the photoelectric conversion parts of a second pixel are exposed for a second exposure time shorter than the first exposure time, and pixel signals generated in the plurality of photoelectric conversion parts of the second pixel exposed for the second exposure time are output separately.
(18)
The solid-state imaging device according to any one of (1) to (16) described above, in which
of the plurality of pixels included in each pixel set, the photoelectric conversion parts of a first pixel are exposed for a first exposure time, the photoelectric conversion parts of a second pixel are exposed for a second exposure time shorter than the first exposure time, the photoelectric conversion parts of a third pixel are exposed for a third exposure time shorter than the second exposure time, and pixel signals generated in the plurality of photoelectric conversion parts of the second pixel exposed for the second exposure time are output separately.
(19)
The solid-state imaging device according to any one of (1) to (18) described above, in which
the color filters in the pixel sets are arranged in a Bayer array.
(20)
An electronic apparatus including:
a solid-state imaging device including
a plurality of pixel sets each including color filters of the same color, for a plurality of colors, each pixel set including a plurality of pixels, each pixel including a plurality of photoelectric conversion parts.
REFERENCE SIGNS LIST
- 1 Solid-state imaging device
- 2 Pixel
- PD Photodiode
- TG Transfer transistor
- 3 Pixel array
- 5 Column signal processing circuit
- 12 Semiconductor substrate
- 31, 32 Semiconductor region
- 36 Inter-pixel light-shielding film
- 37 Color filter
- 38 On-chip lens
- 51 (51Gr, 51Gb, 51R, 51B) Pixel set
- 91 On-chip lens
- 101 Insulating layer
- 102 Impurity layer
- 121 Light-shielding film
- 200 Imaging apparatus
- 202 Solid-state imaging device
Claims
1. A solid-state imaging device comprising:
- a plurality of pixel sets respectively including color filters of a same color, for a plurality of colors, each pixel set including four pixels, each of the four pixels including two photoelectric conversion parts, each pixel set further including a charge holding part that is coupled to the two photoelectric conversion parts of all of the four pixels in the pixel set.
2. The solid-state imaging device according to claim 1, wherein
- each pixel includes the two photoelectric conversion parts disposed symmetrically in a vertical direction or a horizontal direction, and
- orientations of the two photoelectric conversion parts of the respective pixels are in a same direction.
3. The solid-state imaging device according to claim 2, wherein
- the orientations of the photoelectric conversion parts of the pixels are in the same direction in all the pixel sets.
4. The solid-state imaging device according to claim 1, wherein
- each pixel includes the two photoelectric conversion parts disposed symmetrically in a vertical direction or a horizontal direction, and
- orientations of the two photoelectric conversion parts of two of the pixels that are in the horizontal direction in each pixel set are in a same direction.
5. The solid-state imaging device according to claim 1, wherein
- each pixel includes the two photoelectric conversion parts disposed symmetrically in a vertical direction or a horizontal direction, and
- orientations of the photoelectric conversion parts of two of the pixels that are arranged in the horizontal direction in each pixel set are in orthogonal directions.
6. The solid-state imaging device according to claim 1, wherein the two photoelectric conversion parts of each pixel are isolated from each other by an insulating layer.
7. The solid-state imaging device according to claim 1, wherein the two photoelectric conversion parts of each pixel are isolated from each other by an impurity layer of a conductivity type opposite to a conductivity type of the two photoelectric conversion parts.
8. The solid-state imaging device according to claim 7, wherein
- the impurity layer forms a potential barrier lower than a potential barrier at pixel boundaries.
9. The solid-state imaging device according to claim 1, wherein
- a light-shielding film is formed at some of the plurality of pixel sets, the light-shielding film partly shielding all the pixels in each pixel set from light.
10. The solid-state imaging device according to claim 1, wherein
- a light-shielding film is formed at some of the plurality of pixel sets, the light-shielding film entirely shielding some of the pixels in each pixel set from light.
11. The solid-state imaging device according to claim 1, wherein the charge holding part is configured to add and output charges generated in the two photoelectric conversion parts of all of the four pixels.
12. The solid-state imaging device according to claim 1, wherein
- of the two photoelectric conversion parts of the four pixels included in each pixel set, a first photoelectric conversion part and a second photoelectric conversion part are exposed for different exposure times.
13. The solid-state imaging device according to claim 12, further comprising:
- a control unit that performs control to output charges of light received by each photoelectric conversion part as a pixel signal,
- the control unit outputting a first pixel signal of the first photoelectric conversion part exposed for a first exposure time, and outputting a second pixel signal of the second photoelectric conversion part exposed for a second exposure time.
14. The solid-state imaging device according to claim 1, wherein
- pixel signals generated in the two photoelectric conversion parts of at least some of the four pixels included in each pixel set are output separately.
15. The solid-state imaging device according to claim 1, wherein
- of the four pixels included in each pixel set, the photoelectric conversion parts of a first pixel are exposed for a first exposure time, the photoelectric conversion parts of a second pixel are exposed for a second exposure time shorter than the first exposure time, and pixel signals generated in the plurality of photoelectric conversion parts of the second pixel exposed for the second exposure time are output separately.
16. The solid-state imaging device according to claim 1, wherein
- of the four pixels included in each pixel set, the photoelectric conversion parts of a first pixel are exposed for a first exposure time, the photoelectric conversion parts of a second pixel are exposed for a second exposure time shorter than the first exposure time, the photoelectric conversion parts of a third pixel are exposed for a third exposure time shorter than the second exposure time, and pixel signals generated in the plurality of photoelectric conversion parts of the second pixel exposed for the second exposure time are output separately.
17. The solid-state imaging device according to claim 1, wherein
- the color filters in the pixel sets are arranged in a Bayer array.
18. An electronic apparatus comprising:
- a solid-state imaging device including
- a plurality of pixel sets respectively including color filters of a same color, for a plurality of colors, each pixel set including four pixels, each of the four pixels including two photoelectric conversion parts, each pixel set further including a charge holding part that is coupled to the two photoelectric conversion parts of all of the four pixels in the pixel set.
19. The electronic apparatus according to claim 18, wherein
- each pixel includes the two photoelectric conversion parts disposed symmetrically in a vertical direction or a horizontal direction, and
- orientations of the photoelectric conversion parts of two of the pixels that are arranged in the horizontal direction in each pixel set are in orthogonal directions.
20. The electronic apparatus according to claim 18, wherein the charge holding part is configured to add and output charges generated in the two photoelectric conversion parts of all of the four pixels.
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Type: Grant
Filed: Nov 12, 2018
Date of Patent: Feb 22, 2022
Patent Publication Number: 20200358989
Assignee: Sony Semiconductor Solutions Corporation (Kanagawa)
Inventor: Kozo Hoshino (Tokyo)
Primary Examiner: Nhan T Tran
Application Number: 16/764,474
International Classification: H04N 9/04 (20060101); H04N 5/369 (20110101); H04N 5/355 (20110101);
